Fiberglassing 5inchs too transom

[94patrol]

Hey guys getting a new motor in a month or soo and I'm gona go with a 25inch leg just to get it up a little higher and want to glass 5inchs onto the old transom witch is only 12months old I am thinking io just bogging in 38mm ply and and glassing it straight to the old trasom with 6 layers of 450csm will this be ok? It's a old 5.2 seafarer Viking

[Noelm]

Not too sure just "joining" the transom will be successful, the new part will need to be made solid to the original part, maybe long dowels down into the old bit and glassed in?

[94patrol]

Yea it's a hard one I'm sure it's being done befor but couldnot find anything on here I might go see a fibreglass mob tomorrow I don't really want a jacking plate

[fisho64]

have a look at where the bolts will go if it sits up 5"
if the bolts are still well in the original transom, all the top piece will need to do is space out the gap.
If the bolts are in the new part or near then it'll be structural

[Rip it up]

I would say that a joint will never hold the forces of the top bolts pushing on it. No way I would be tagging a piece on there.

Just my opinion though, someone might have successfully done it before.


Damo's dodgy boat building repair centre.

[Shark Poker]

We have all seen it done with alloy and sst extensions.
What s your most likely approach Damo?

[Duckfish]

What about a 5/6mm stainless plate across your transom. Saw a boat with the plate at Tin Can Bay and thought that was a good idea when it came time for me to replace my motor.
Duck

[Rip it up]

Hey poker. I was going to suggest a stainless bolt on attachment piece. But then thought for the price of the stainless fabrication you could get the transom rebuilt with glass.

Assuming that last rebuild on the boat was done successfully with new stringers and floor, it wouldn't be an easy job to remove that's for sure. But I would attempt it like this:
Do the repair from the inside.
Cut the rear capping off the top deck, through the gunnel rubber flange and about a meter up the sides. Cutting the transom join just behind the timber transom.
With the cap removed I would look at a horizontal line just above the floor height. And run a circular saw along the floor line into the transom timber. Deep enough to get the two layers but not touch the external skin.
Then create a 2" grid using saw cuts into the timber. Vertically and horizontally.
This would allow a chisel to be used and separate the unsaturated ply layers away from the glass layup inside. Big session of chippy away the timber squares. But if you get a few squares back to the glue on the external skin you will be knock massive checks off it no time. Not as itchy either.
Then it would be a matter of going pyscho with the grinder to remove the sections in the corners and the glue stuck to the external skin.

The timber overlapping section just off the floor could be given a scarf joint tapered at 45 deg down to the floor timber. Grinding back the floor 8" to allow the over lap to be spread onto the floor.

Then create the new 25" transom like any other normal transom but it would be a rectangle base not a triangle. Scarf the bottom join and cove and overlap the internal glass layer onto the floor. Use an epoxy thickened with milled glass fibres for the scarf joint.

Well that's my thoughts. But I'm sure someone might have had a similar scenario either with a good sound transom going up in size or used the plate bolt on method.

Interesting topic though.


Damo's dodgy boat building repair shop.